1. Field of the Invention
The present invention relates to a bonded structure provided with a carbon nanotube, and to an interconnection, a single electron transistor and a capacitor in which a carbon nanotube is incorporated.
2. Description of the Related Art
Recently, nano-devices have been very actively developed based on the so-called nano-processing technique. A nano-device can be operated merely by several electrons, therefore power consumption can be significantly reduced in comparison with a conventional silicon-based device, besides an element size can be dramatically diminished.
For the development of such nano-device, introduction of a carbon nanotube is being intensively studied. A carbon nanotube is constituted of cylindrically connected graphite sheets. A carbon nanotube can be selectively made up into materials having properties that are typical of various products ranging from a semiconductor to a metal through a control of chirality etc. without doping impurities, therefore offers a vast potentiality as a constituent of an integrated circuit including a nano-device. The JP-A (laid open) No. 2002-118248 discloses an electronic device in which a carbon nanotube is incorporated.
For manufacturing such nano-device a high-level refined processing technique is required for integrating various elements on a substrate as well as connecting those elements via refined interconnections.
However a rounded surface of a carbon nanotube has a stable hexagonal ring structure which is not chemically active in general, so it is difficult to join a carbon nanotube to an interconnection, a pad or another element.
Also, when it comes to designing a quantum-effect nano-device in which a quantum effect of a single electron transistor etc. is utilized, the requirement for the refined processing technique is more severe. For instance, in designing a single electron transistor, it is essential to form an ultra-thin insulating film that permits formation of a tunnel barrier between a source/drain electrode and a Coulomb island. If the insulating film is too thick the electron cannot pass through the insulating film, while if it is too thin the electron can freely pass by. Further, in order to prominently obtain unique characteristics originating from the quantum effect, the Coulomb island has to be as small as for example 50 nm or smaller. Studies on the single electron transistor have so far been aggressively performed as observed in the JP-A (laid open) No. 2001-77346 and JP-A (laid open) H9-69630, however nearly none of those studies have successfully achieved a high-level control of a size of a tunnel layer or a Coulomb island, to thereby make full use of the characteristics obtainable from the quantum effect.